Control system for electromagnets.



V J. H. HALL. CONTROL SYSTEM FOR ELEGTROMAGNETS.

. Anu mnon FILED HAY'13, 1910. I 967,186-, I Patented Aug. 16,1910.

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Patented Aug. 16,1910; w

INVENTOR 1 11 HALL GON'JIBOL SYSTEM FOR EL ECTROMAGNETS.

AlfPLIOATION I;LED HAY 13", 1910. I

I WITNESSES a W omreo sr rrns PATENT carton TAX H. HALL, OF CLEVELAND, OHIO, ASSIGNOR TO THE ELECTRIC COhT'IBOLLER AND MANUFACTURING- COMPANY, OF CLEVELAND, OHIO, A CORPORATION OF OHIO.

common mm FOR mincraomnenn'rs.

Application filed May 13, 1910. Serial No. 561,100.

To all whom it may concern:

Be it known that I, JAY H. HALL, a citizen of the United States, residing at Cleveland, in the county of Cuya-hoga and Statev of Ohio, have invented new and useful Improvements in Control Systems for Electromagnets, of which the followingis a specification.

My invention relates to systems of control for electro-magnets and has particular refereuce to that type. of electro-magnets known u been found that, owing to t as lifting magnets.

In the use of large liftin magnets it has v Tie-time required.

for them to become de-magnetized, they do not drop theirloads for some time after the magnetizing current has been'cut oil. Inorder to cause the magnets to release their loads more quickly, a limited amount of current has been put through their windings in the direction opposite that during the energization of the windin s. Heretofore, when loads, such as layers 0 billets or rails,

are being moved-and arranged in piles the operator, in lowering the loads and releasing the same by moving the master-switch to the-drop-position, sometimes fails to move the master-switch to the oil-position before hoisting the ma netj from the pile. The small amount 0 magnetism produced by the reverse current may cause one-or more billets or rails to be lifted from the' pile,

" pivoted so as to engage the contacts a and if, or the contacts a and (1*.

supports for the blades S and S are connected to the winding the lifting magnet M by the wires 1, 2, and 3.

'D is a relay having its winding (1 connected by the wires 5 and 6 to the contact a and by the wire 7 to the wire 1. The fixed contacts of the relay D are connected to the wires 8 and 5, which include the resistances R and K, respectively. The contacts a 1 and a are connected by the wire 4. .The

supply circuit is connected to the contacts a and (1 To energize the magnet M,-the switch S is thrown to the uposition shown in fulllines and the circuit 1s established from the positive through the switch blade' S, the

wires 1 and 2, the magnet coil m, thewire 3, and the switc'h blade 2 to the negative. To

merelyopen the circuit the switch 8 is opened; but to cause the load which has beenlifted by the magnet to drop quickly, a reverse current limitedby the resistances R and R is allowed to flow in the magnet by throwing the switgi S to the down-position shown in dotted lines. The discharge voltage from the magnet due to the'current wires 7 and 2 to the other terminal of the magnet.

The current in this circuit causes the relay D to close its contacts (P, and a circuit is established as follows: from the positive through the resistance R, the wire 8, the contacts the resistance R, the wire 5, the switch blade S, the Wire 3, the magnet coil m, the wires 2 and l, the switch blade S, andthe wire 4 to the negative. It will be noticed that this current passes through the magnet coil in a direction reverse to that when the.ma'gnet is energized directly fromthe line, and is limited by the resistances R and R This limiting current can be made large enough to cause the load to drop even before it has reached its full value, and thereby greatly decrease the length of time for the magnet to drop its load after the switch S has been placed in the down-position. The operating windingd continues to hold the contacts d closed until the discharge voltage of the magnet becomes less'and less due to the current through the magnet approaching a constant value, and the relay D may be adjusted so that it will drop open at a voltage correspondin to the voltage existing across the terminafi of the magnet at the time the load is released from the magnet.

I have shown the high resistance R connected across the iixed contacts of the relay D. This resistance remains in the reversecurrent circuit when the relay contacts are opened; The resistance R may be omitted and I have not shown it in Figs. 2 to 4, but they may contain them, if desired. I prefer to 'omit the resistance R, but have illustrated it. toshow that it is not absolutely --essential to open the reverse-current circuit.

similar parts on Fig. 1.

' Referring now to Fig. 2, the parts are The switch S cooperates with the contacts a and a only,

other side of the line.

the contacts a and a of Fig. 1 not being required. The relay D has the additional contacts J inserted between the resistance IR and one .side of the line, and the contacts 01 between the resistance R and the The solenoid winding d" is so designed that it will not cause the contacts (5 and ol to close when the voltage of the supply mains is applied thereto, -but so that it Will close them when subjected to the high inductive discharge voltage of the magnet M. The operation then is as follows: To energize the magnet for attracting its load, the switch S is closed.

When it is desired to drop the load the switch S is opened whereupon the high inductive discharge voltage of the magnet causes the relay D to close its contacts, and

. a circuit is established through the contacts (l and d and the resistances R and R through the magnet winding m in a di-rec-- tion opposite to that .when it was energized by closing the swltch- S. This current continues. to rise until the. voltagehas fallen to a point where the relay D opens its contacts, at which time the reverse current will be cut off."

1 Referring now to Fig. 3, I show another form ofmy invention, in which a magnetically operated switch S is used in place of "the hand-o erated switch S shown in Fi s.-

1 and 2. en it is desired to energize t e magnet M, the arm 0 of the master-switch O is moved from the git-position to the position marked Lift, where the brush a connects cuts a and 0?. 'A circuit is then established "from the positive throu h the wire 5', the segment 0 the brush 0', t e segment .0, the wire 6, the operating soleno1d 8 of the switch St, and the wires 7 and 3 to the negative. -.The.current in this circuit causes the switch S to close its contacts 8' and s and open its contacts 8 and s. The

circuit through the magnet is now' from positive through the wire 1*, the contacts 8', the wire 2', the winding m of the magnet M, the wire 4", the contacts.s-, and the wire 3* to the negative. The magnet by means'of a v suitable crane can now lift its load and con vey it to any desired place, where the magnet is lowered until the rails rest upon the support, on which it is desired to place ated by the same reference characters tense them. If is now desired td release; -ralls quickly, thecontroller armc is thrown brush 0 connects the segments 0 and c. As soon as the brush 0 leaves the segments and s cutting oil the current from the magcauses the operating solenoid d of the relay D to be energized through the followin circuit: from one terminal of the magnet through the wires ,4? and 8, the contacts 8,

11, 'and 2. to the other terminal of the magrelay to close its-contacts d and the reverse current circuit is established from the posi- 0 the brush 0, the segment 0 the wire 16, the resistance'R, the wires 17 and 4:, the

R the'wire 14, the contacts 8 and the wires 15 and 3 to the negative. The reverse current circuit being now established continues magnet, allowing the load to drop, at which time the relay causes its contacts (Z to open,

these contacts at a time shortly after they load would be released. now be raised oifthe rails without an danger of carrying the rails with it or many way disturbin the pile on which they have beendeposite. connected to the contacts 01 of the-relay D. which are closed whenever the contacts d are open. One terminal of this signal lamp is connected to the segment 0 through the wires 18 and 16, and to the negative side of the contacts 8 and the wires 15 and 3 "Whenever tli'e master controller arm 0 isinthe positionmarked Drop, and the 113% verse current'has reached such a point that";

F'willbe" at heicanv the load will be dropped, the lamp lighted to notify the operator t the load which he has just deposited.

magnetize it when the master switch is in the Lift position. switch is in the Drop position current passes through the magnet in the reverse dicausing the magnetism to be .reversed, al*

P is controlled by the reverse current and is arranged to operate when the reverse current reaches its maximum or\ nearly so.

\Vhen the switch P operates, it cuts off the the wire .9, the solenoid d, and the wires 10,

. 8O net. The current in this circuit causes the.

the relay D having been adjusted to open move the magnet safely without disturbing rection, limited by the resistances 'r' and 1- to the position Drop at whic'htime its 0 and c the switch S opens its contacts 8 net,and the contacts 8 and 8* close. The dlscharge voltage from the magnet now tive through the wire 5*, the segments a and magnet winding m, the wires 2, 11, and 12, the contacts 03 the wire 13, the resistance" ,to flow until the magnetism is reversed in the i The magnet can A A signal lamp 1s shown at L, which is,

the source of supply through the wire 20, 7

Referring to Fig. 4, S 1s a magneticswitch which causes current tobe supplled-ip to the winding m of the magnet Mto" fully-=' \Vhen -the master lowing theload to drop quickly. The switch 9 some. a

reverse current from the mii'gnet and-"establi'she's a'holding circuitto hold the switch 1n the operative'position so long as the inaster switch remains in the Drop osition. The'operation is-as follows: en the master-"switch handle ismoved to positionmarkedIlFLift-fi 5a circuit is. established .througlii'the magnetizing windings" of the switch S?.-. .from; 'thewpositive thro'u h the wire 1!, thecontact a, the" fin er of; t econtact c1;- the wire- 2", the. winding 8", and the wire State the negative; -This causes the switch S to close its contacts .5 ands, and the nalgnetll lis energized by the current from t e, positive" through the contacts 8',

the wire 4'?, themagnetwinding m, the wire swan-d the "contacts a to the negative.

The "er; is ncv'vv fullyenergized and will pick tsload.v itJis-desire'd to release the load the ndle c .is inoved to the position Dlop,lflwhereupon the switch S r sweet s and" a the winding 8 'heingdeiinergizsd as soonxasthe finger c? 'r zewerssiiii ec fl avest heteent'eema A new circuit is stab "lished thronghjthe ma net windin m in a ion'as fol owe: from he osi- .tiv'e through the Wire 1,-the contact a, the

sis nice 1 rhe'wire' 5", the magnet winding m, the wires 4" and '7", the contacts p, the

wires 18" and 9 the magnetizing winding p, the"w1re- 10 the -r'esistainie- 1", the wire 11",

and the contact 8" to the negative.

the magn ter handle; in

I l The magnetism dueto this reverse. current asses through zero and the load is released. on

the-reverse current reaches a maximum or nearlyso, the wlndlng causes the switch contact c, the wire 6, the resistance 1", the

wire 12", the contacts the wires 13 and 9'3, the windin p, the wire 10", the resist; ance r the wire 11", and the contacts 8 to the ne ative. The current in this circuit holds t e switch P in a position to keep the contacts p open as long as the ster switch handle '0' is in the position, marked Drop, and after the reverse current has reached a value suflicient to drop the load. On moving the handle a to the Ofi' position the switch winding-p is de'einergized, and the switch P is restored to its normal position.

extited: by'm'oving the master hind-1e from theh-ft-position to-the off-position, but

magnet zed, and the load will take some time. to release. v 1 r As shown .in Fig.1 the current in the reverse-current circuit is upon the opening of the contacts d", cut down by the resistance R*= to such a value as to prevent the flow of. a current which-would cause the me not when lifted to raise any part of the oad. which it deposits; v

In Figs. 2 to' i, the resistance R though omitted may be regarded as having its place supplied by the gap at the contacts (I where is, an infinitevalue.

I claim v '1. A magnet having an energizing winding, switch-mechanism, and connections concurrents to'flow successively througr the winding in opposite directions and to interfruptthe second energizing current when it reaches a predetermined value.

2. A magnet having an energizing winding, switc -mechanism, connections con:- struct'ed and arranged "to cause energizing currents to flow successively through the winding in opposite directions and to interrupt the secondenergizing current when it reaches a predetermined value, and means to limitthe value of the second energizing cur rent.

3. A magnet having anenergizing winding, switch-mechanism, and connections con structed and arranged to cause energizing current ,to flow successively th-roug the winding in opposite directions, the switchmcchanism containing a winding controlled by the dis c harge voltage ofthe magnet winding and controlling contacts which interrupt the reverse current when it reaches a predetermined value. I

4. In a controller for electro-magnets, the combination of switches for reversing the connection of the magnet winding to the supply mains, a resistance for limlting the flow. of current in one direction, and means for automatically interrupting the said current'from the magnet when the said current v has reached a certain value 5. In a controller for lifting-magnets, the combination of a magneticall operatedswitch for connecting the-win ing of the magnet to the supply mains, a master switch, having contacts for energizing the winding of said magnetically operated switch, and contacts forclosing the circuit of the winding of said ma net to give a reverse direction of current ow through said winding, and means for causing said reverse a certain value. 1

'Thefniagnet'Mlean be de nigized the the magnet will be slow in becoming-den the resistance hasreached its maximum, that structed and arranged to'cause ener izingcurrent to be interrupted after it has reached 6. In a lifting-magnet controller, the combination-of a magnetically-o erated switch having main contacts whic connect the magnet winding to a source of energy, and having auxiliary contacts arranged to close when the main contacts are open and to open when the main contacts are closed, a master switch having contacts arranged to connect the winding of said magnetlcallyoperated switch to a source of supply, and also to connect the winding of the magnet to the'source of supply so that the current will flow through the winding in a direction opposite to that in the first connection, said circuit containing the said auxiliary contacts, and means for automatically opening the circuit of said magnet winding when the current reaches a certain value.

7. For reversing the current throu h a liftin magnet to cause it torelease its oad, an e ectro-magnet having its operating winding connected to the magnet terminals and responsive to the high discharge voltage of the magnet when its circuit is opened, a

switch operable by the said winding to close a circuit through the lifting magnet in a direction opposite to that previously existing therein. v

8. An inductive winding, means for connecting said winding to a source of supplyto pass current through said winding in one direction, and a second means responsive to the discharge voltage of the said winding for connecting the said winding to a source {it of supply to pass current through said winding in a reverse direction.

9. An lnductive' winding, means to pass current through said winding in one direction, a second means responsive to the discharge voltage of the said winding for connectmg the said winding to a source of supplyto pass current through said Windin in a reverse direction, and constructed an arranged to automatically cut ofi' said re for connectmg said winding to a source of supply verse current when it has reached a certain value.

magnets containing energizing windings, WhlCh consists of connecting the magnet winding to a source of supply to ene; gize it for attracting a load, disconnecting it] from .the said source and reconnecting it toithe source of supply so that the current flows in a reverse direction through the magnet winding to cause the load to be released, and automatically interrupting the reverse released.

Si ned at Cleveland, Ohio, this 11th day of ay, A. D. 1910.

" JAY H. HALL.

Witnesses: V

. R. H. BENNETT, H. M. DIEMER.

.current at or near the time that the load is a 

